The present invention relates to the tooling field, and more particularly to tools used for disassembling bolt and nut assemblies.
Power torque wrenching tools have been known and used for years in manufacturing and maintenance industries to replace manual tools such as hand wrenches used for installation and removal of bolt and nut assemblies commonly employed for securing various parts together. Typically, power torque wrenches are provided with a rotary holder adapted to receive a selected socket or gripper designed to fit with the outer surface of the nut or bolt head to be tightened or removed from a secured structure. Known power torque wrenches, either be powered through pneumatic, hydraulic or electrical energy, are generally provided with a suitable mechanical or electrical switching device to allow either assembly or disassembly functions. For the particular case of nut and bolt assemblies, a nut can be either tightened on or removed from a corresponding nut, respectively. Examples of such prior art tools are disclosed in U.S. Pat. No. 5,301,574 to Jung et al. and in U.S. Pat. No. 5,357,828 to Spirer. In order to facilitate the use of heavy torque wrenching tools by operators, many tool holders have been proposed for that purpose, examples of which are disclosed in U.S. Pat. No. 4,265,147 to Fox; U.S. Pat. No. 4,271,730 to Holl et al.; U.S. Pat. No. 4,498,545 to Grassi et al.; U.S. Pat. No. 5,245,895 to Yoshida et al.; U.S. Pat. No. 5,390,568 to Pietras; U.S. Pat. No. 5,544,554 to Brightly; U.S. Pat. No. 5,692,418 to Burner; and U.S. Pat. No. 5,690,005 to Jung et al.
In many applications, a complete disassembly of bolts and corresponding nuts mounted on a receiving structure is required, in order to allow further operations, such as disassembly of the structure. For a structure where bolt heads are hidden, the operation involves removal of each nut from the threaded rod of a corresponding bolt protruding from the structure. Then, there is a need to withdraw the bolt by axially pushing it throughout the structure, which bolt is expulsed from the hidden side of the structure. For example, such procedure is required for the maintenance of crushing mills used in the mining industry, wherein worn crushing liners bolted through the inner walls of the mill crushing tumbler have to be periodically replaced. In such a case, following the removal of a nut from a corresponding bolt, the latter is generally jammed and therefore cannot be easily removed by the operator, mainly due to corrosion and dirt accumulation at the interface between the bolt and the material defining the receiving opening provided on the structure. The use of a separate manual tool, and preferably a heavy power tool such as a hydraulic or pneumatic percussion hammer is then required to complete the disassembly, requiring further hard tool handling from the operator while reducing working productivity.
It is therefore an object of the present invention to provide an apparatus for disassembling a threaded bolt and nut assembly which facilitates both nut removal and bolt removal from a receiving structure.
According to the above object, there is provided an apparatus for disassembling a threaded bolt and nut assembly, the bolt initially extending through an opening provided on a structure and being secured thereto with the nut axially mounted on a threaded rod of said bolt. The apparatus comprises a tool body, a nut gripping element mounted for rotation on a working portion of the tool body, the gripping element being provided with a bore axially extending theretrough. The apparatus further comprises a rotary actuator mounted on the tool body and operatively coupled to the nut gripping element for imparting torque to the mounted nut in a direction allowing release of the nut from the secured bolt. The apparatus also comprises a pushing device mounted on the tool body and provided with an elongated push member having a working end being axially displaceable within the bore, and a linear actuator mounted on the tool body and operatively coupled to the pushing device for selectively displacing the push member between a retracted position allowing the release of the mounted nut and an extended position where the bolt is at least partially withdrawn from said opening upon thrust of the working end of the push member. Means are also provided for controlling the rotary actuator and the linear actuator.